61531661 has 8 divisors (see below), whose sum is σ = 62672064. Its totient is φ = 60397920.

The previous prime is 61531637. The next prime is 61531669. The reversal of 61531661 is 16613516.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61531661 - 2¹⁸ = 61269517 is a prime.

It is a super-2 number, since 2×61531661² = 7572290610837842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61531669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19361 + ... + 22313.

It is an arithmetic number, because the mean of its divisors is an integer number (7834008).

Almost surely, 2^61531661 is an apocalyptic number.

It is an amenable number.

61531661 is a deficient number, since it is larger than the sum of its proper divisors (1140403).

61531661 is a wasteful number, since it uses less digits than its factorization.

61531661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3331.

The product of its digits is 3240, while the sum is 29.

The square root of 61531661 is about 7844.2119425727. The cubic root of 61531661 is about 394.7900630928.

The spelling of 61531661 in words is "sixty-one million, five hundred thirty-one thousand, six hundred sixty-one".